150 likes | 510 Views
CENTRIFUGE WITH ADJUSTABLE SPEED AND DIRECTION OF ROTATION. English military engineer Benjamin Robins (1707–1751) invented a whirling arm apparatus to determine drag . In 1864, Antonin Prandtl invented the first dairy centrifuge in order to separate cream from milk.
E N D
English military engineer Benjamin Robins (1707–1751) invented a whirling arm apparatus to determine drag. • In 1864,Antonin Prandtl invented the first dairy centrifuge in order to separate cream from milk. • In 1879, Gustaf de Lavaldemonstrated the first continuous centrifugal separator, making its commercial application feasible.
INTRODUCTION • A centrifuge is a piece of equipment, generally driven by a motor, that puts an object in rotation around a fixed axis, applying force perpendicular to the axis. • The centrifuge works using the sedimentation principle, where the centrifugal force is used to separate substances of greater and less density.
PRINCIPLES OF CENTRIFUGE • The centrifuge works using the sedimentation principle, where the centrifugal force is used to separate substances of greater and less density. • Basis of separation: • Size • Shape • Density
CENTRIFUGAL FORCE • Let us consider a body of mass m rotating in a circular path of radius r at a velocity v. The force acting on the body in a radial direction is given by: F = mv^2 / r • The same body experiencing gravitational force. This can be expressed as, G = mg
The centrifugal effect is the ratio of the two forces, so that: C = F / G = mv2 / mgr = v2 / gr But v = 2πrn So, F / G = (2πrn)2 / gr = 4π2r2n2 / gr = 2 π2n2d / g ------------------------ (1) g = 9.807 m/s^2 Centrifugal effect = 2.013 n2d Provided that n is expressed in s-1 and d is in meter.
METHODOLOGY Induced gravitational field Supernatant Precipitate In process Suspension Separation complete • Pellet • Supernatant • Relative centrifugal force or Centrifugal effect
MATERIALS OF CONSTRUCTION A centrifuge is comprised of two major components • The drive mechanism Thedrive mechanism is the source of rotary motion, and is powered by an electric motor, by air pressure, or by oil turbines, depending upon the type of centrifuge. • The Rotor The rotor is the large rotating element of a centrifuge into or onto which samples are loaded. It is driven about a fixed axis (or shaft) by the drive mechanism, with expenditure of large amounts of energy.
TYPES OF ROTORS • Fixed Angle Rotor
APPLICATIONS OF CENTRIFUGE • Production of bulk drugs • Production of biological products • Biopharmaceutical analysis of drugs • Evaluation of suspension and emulsion • Blood plasma is separated from whole blood • Different particle size fractions are separated by using control of speed of rotation and rate of flow
ADVANTAGES • Faster and reliable • Several specimens can be centrifuged at ago e.g. blood &urine • Not tiresome as compared to manual centrifuge machine • Safe once the specimen are enclosed into the machine
DISADVANTAGES • Time wasting to the patient • Exhausting of the laboratory technician • Specimens may spill out of the test tubes • The capacity is limited.
CONCLUSION • Thus, we can see that the centrifuge machine is an essential medical device for every biological and clinical laboratory as well as medical practice. • The centrifuge may seem a rather common machine, but newer models have become more complex, as higher speeds have become necessary for certain processes and applications and as more precise controls are needed.
BIBLIOGRAPHY • ezinearticles.com • wikipedia.com • google.com • alibaba.com